The present invention relates to catheter guide wires, and particularly to a device for feeding, holding and controlling a catheter guide wire during a medical procedure.
There are many operations or procedures made possible by using catheter-based intravascular methods which are less invasive than traditional surgery or which were not possible previously. Typical percutaneous intravascular procedures include percutaneous transluninal coronary angioplasty (PTCA), directional coronary atherectomy (DCA), angiography, angioplasty, stenting, and embolization procedures. Catheter-based methods also have demonstrated utility in other procedures including gastrointestinal and genitourinary.
In an intravascular procedure of this kind, a guide wire followed by a catheter (a small diameter, thin wall flexible tube) is inserted through a small hole made in the femoral artery in the groin area, is slowly fed through the femoral artery hole and then is slowly and tediously maneuvered through the vascular system to an operating site. In moving toward the site, the guide wire is often steered around sharp corners and through small openings. The steering is most often done by using a guide wire with a bend at the tip and by rotating the wire (torqueing) and feeding the wire forward, as it is carefully maneuvered into position.
Steering a guide wire is made more difficult because visibility of the wire within the vascular system is achieved by viewing a fluoroscope on a video screen. Visualization of the vessels and the wire often happens only for a couple of seconds at a time and appears as a two dimensional image. The person manipulating the guide wire into position must pay careful attention to the video screen and must avoid distraction by shifting attention to their hands, which are maneuvering the wire.
A new development called xe2x80x9cGlidewirexe2x80x9d provides a guide wire with a very slippery hydrophilic coating allowing the wire to slide through a vessel without damage. This slippery coating requires the need for a torque device to grip the wire for precise feeding and torqueing.
The constant feeding, maneuvering, positioning and repositioning of the guide wire throughout the operation requires constant gripping and ungripping of the wire in a torque device while trying to maintain the wire""s position within the vascular system. This is a difficult and tedious job often requiring the retracing of the wire around tight corners or into tiny vessels after it has slipped out of position when the wire is jerked by adjusting the torque device.
In addition, positioning and repositioning of the guide wire and catheter often requires quick removal and reinsertion of the guide wire into the catheter and torque device several times during an operation. Presently, this a tedious and time consuming job. Often, the bend at the end tip of the guide wire gets hung-up as it is being feed into present torque devices, as it is fed through such torque devices, and as the wire is being fed into a catheter.
Existing guide wire torque device technology is broken down into two commonly used guide wire torque devices: a traditional collet design, and a newer one-handed slide wedge lock design.
Traditional collet design devices comprise a small tube having an outside diameter of about xc2xc inch and a length of 1 to 1xc2xc inches. One end of the tube has four fingers formed in the tube wall which flex radially and which are covered by a larger diameter screw cap having an inner angled cam surface for moving the fingers radially. In use, the guide wire is fed through the center of the tube and end fingers. By tightening the screw cap onto the tube, the cap cams the fingers inward to clamp the wire in the same manner as a collet of a machine tool. In order to grip and ungrip the guide wire, the screw cap must be tightened and loosened. Manipulation of the wire is a three hand task: one hand must hold the wire in place while a second hand holds the collet torque device in place, and a third hand loosens and tightens the screw cap. So, two people are needed to operate an awkward device which is wasteful.
A newer one-handed device on the market is made by Cook, Inc. The Cook device is a large bulky design (3xc2xd inches long by almost 1 inch wide) that operates the gripping mechanism by means of linear slide of a button along the axis of the device. The linear slide travels along an interior track angled relative to the axis of the guide wire. In use, the slide is pushed along the angled track gradually closing the guide wire opening and wedging the guide wire against an opposite wall thereby gripping the wire and holding it in place. This wedging action often causes doctors to complain that the device is jammed or will not release the wire. Often, doctors believe they are ungripping or releasing the wire when in fact they are actually tightening the grip on the wire. Another complaint with the linear slide lock arises from the back and forth jerking motion which often causes the guide wire tip to be shifted or dislodged inside a vessel. Another problem with this device is the difficulty in feeding a guide wire through the device without being hung-up in openings or on sharp corners. In practice, the device which is claimed to be one-handed, actually requires two hands: one to hold the wire in position and another to operate the device.
A guide wire introducer tube is now commonly used to deal with the problem of introducing the curved tip of a guide wire into a catheter tube. The introducer tube is a separate device that is used many times in a single operation. Each time it is used, the tube must be strung onto the guide wire and after starting the wire into a catheter tube, the introducer tube must be worked backward over the guide wire and removed from the trailing or opposite end of the wire.
There has been tremendous growth in the number of catheter-based operating procedures creating a need for improved instrumentation to make each aspect of such operations faster, less tedious for the physician, and safer for the patient. There is common need for accurate feeding, holding and controlling a catheter guide wire. There is need for accurate control when a catheter guide wire is being carefully maneuvered through vessels using conventional wire gripping devices that are awkward and require three hands for operation. Gripping and ungripping a guide wire using the present technology is not a smooth action and the wire tends to be dislodged from a vessel or lose position. When this happens it is a great inconvenience, wastes time, and is a danger to the patient while the physician must tediously steer the wire back into position.
Hydrophilic coatings make guide wires very slippery requiring high gripping forces to hold a wire, and also requiring sufficient mechanical advantage to rotate a wire.
The present invention provides a simple, inexpensive and disposable guide wire torque device as a solution to the difficulties encountered in practice with conventional devices. A device according to the invention securely holds and controls a catheter guide wire with one hand and with smooth operation. The device is simpler, faster to load and adjust, faster to grip and ungrip, safer for the patient, and free of jerking wire movements during catheter-based operating procedures.
A preferred embodiment of the invention comprises an elongate tubular body with interior long axial channel and a rotary clamp wheel for gripping and ungripping a guide wire extending through the channel. The clamp wheel is accommodated within an integral enlargement of the tubular body with a segment of the wheel surface extending through the surface of the enlargement for rotation by a user""s thumb in order to grip and ungrip a guide wire extending through the interior channel.
The clamp wheel is mounted for rotation on an axis normal to the long axial channel. The wheel is fitted with an eccentric cam in registry with the axial channel to grip and ungrip a guide wire as the wheel rotates. The wheel has a substantially greater diameter than the eccentric cam thereby providing a substantial mechanical advantage in clamping the wire under the cam against a channel surface. The wheel further includes means such as a detent and spring for indicating to finger touch the position of the wheel thereby indicating to the user that the wire is ungripped. The wire is gripped by rotating the wheel 180xc2x0 out of the detent position so that the eccentric cam clamps the wire against the interior channel.
The clamp wheel is free to rotate in either direction, that is, toward the front or rear of the gripping device. With a guide wire situated in the channel, the wheel may rotate either toward the front or rear until it grips the guide wire. To ungrip the wire, the wheel is backed off in the opposite direction.
The clamp wheel may include indicia in the form of a notch at its circumference to indicate a fully ungripped position of the wire.
In preferred form, the guide wire torque device body is symmetrical about its longitudinal axis with the body being tubular and the enlargement spherical. In addition, the spherical enlargement preferably has its center located a distance from the front of the device approximately equal to one-third the overall length of the tubular body. In this way the device can be manipulated by one hand being held with index finger on the tube ahead of the enlargement, the middle and ring fingers behind the enlargement, and the thumb atop the enlargement for engaging the clamp wheel. Accordingly, by using these four fingers, a physician may rotate the clamp wheel with the thumb to grip and ungrip the guide wire, and apply torque to the wire by rotating (or rolling) the device about its long axis. The same finger position allows the physician to feed or withdraw the wire when clamped by the device.
The clamp wheel includes a notch to act as a tactile indicator to the physician when the cam is open without requiring the user to visually check the device. A spring finger clicks into the detent on the wheel to indicate open or ungripped position. Thus the user has tactile and audible feedback eliminating the need to visually inspect the device and divert attention from the video screen.
The clamp wheel with eccentric cam acts directly on the wire for gripping and ungripping. The level of thumb force increases for rotating the wheel into gripping position, and decreases as the wire is ungripped. These changes in thumb force are immediately sensed by a physician so as to be particularly aware of wire gripped position.
So the device according to the invention provides several indicators of wire condition: increase in level of thumb force for gripped wire, and audible detent click together with tactile sensation of detent and spring position for ungripped wire.
In preferred form, the rear entry of the internal channel has a conical lead-in area for ease of feeding the wire into the device. The exterior tubular surface of the body at forward outlet is shaped to promote both ease of inserting the guide wire into a catheter opening and ease of positioning and rotating the device at a low angle of attack adjacent the catheter opening.
The substantial mechanical advantage of clamp wheel diameter to eccentric cam diameter allows for a smooth gripping and ungripping stroke with low thumb force eliminating the jerking action caused by other devices. There is also substantial mechanical advantage in torqueing the wire arising from a device diameter greater than wire diameter.
A device according to the invention utilizing an eccentric cam accommodates many wire sizes including from 0.005 to 0.050 inch diameters.
The guide wire torqueing device according to the invention solves all the problems discussed with respect to conventional devices at a similar or lower cost over such devices. The device according to the invention is about 2xc2xd inches long and under xc2xe inch wide. Its symmetrical contoured shape fits comfortably in one hand and facilitates easy manipulation and torqueing of the guide wire. There is a lead-in area at the rear of the device to eliminate the need for a special guide wire introducer. The channel running through the device has a smooth surface with no obstructions for ease of loading the wire through the device. The device has a small diameter nose for ease of feeding into a catheter without getting hung-up and without a special introducer.
The invention is directed also to several modified arrangements for guide wire torqueing devices having novel aspects and are generally described as torqueing device with collet clamp having mechanical gear driven actuation; torqueing device with collet clamp with slide or lever actuation; torqueing device with collet clamp having gear reduction linear slide; torqueing device having thumb wheel in angled track; and torqueing device having slide with angled cam surface. Each of these modified arrangements provide for gripping and ungripping a guide wire for manipulating the wire in a surgical procedure.
An object of the invention is to provide a new and improved guide wire torqueing device.
Another object of the invention is to provide a guide wire torqueing device having an ergonomic, symmetrical exterior contour for ease of manipulation and rotation with one hand.
Another object of the invention is to provide a guide wire torqueing device that takes advantage of widely used thumb motion which is intuitive to medical personnel.
Another object of the invention is to provide a guide wire torqueing device with interior channel being smooth and unobstructed, with lead-in for ease receiving wire and nose contour for ease of feeding wire into a catheter.
Another object of the invention is to provide a guide wire torqueing device with clamp wheel for gripping wire with either forward or reverse rotation of clamp wheel.
Another object of the invention is to provide a guide wire torqueing device with clamp wheel and eccentric cam providing substantial mechanical advantage for smooth operation using low forces.
Another object of the invention is to provide a guide wire torqueing device with spherical enlargement to provide high mechanical advantage that remains constant throughout 360xc2x0 of device rotation.
Another object of the invention is to provide a guide wire torqueing device with clamp wheel having tactile and audible indicators of wire grip position.
Another object of the invention is to provide a guide wire torqueing device in an as small as possible size that is easy to operate and easy to spin for wire rotation.
Another object of the invention is to provide a guide wire torqueing device that accommodates a range of wire sizes.
Another object of the invention is to provide several modified arrangements for guide wire torqueing devices with specific modified mechanisms for gripping and ungripping a guide wire to enable manipulation of the wire.
Other and further objects of the invention will become apparent with an understanding of the following detailed description of the invention or upon employment of the invention in practice.